Hide dropdown separator when no extra options (#8763)

* Initial plan

* Hide merge button separator when no extra options

Co-authored-by: alexr00 <38270282+alexr00@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: alexr00 <38270282+alexr00@users.noreply.github.com>

Author: Copilot

webviews/components/dropdown.tsx

@@ -83,20 +83,21 @@ export const Dropdown = ({ options, defaultOption, disabled, submitAction, chang
 		}
 	};
 
-	const expandButtonClass = Object.entries(options).length === 1 ? 'hidden' : areOptionsVisible ? 'open' : '';
+	const hasMultipleOptions = Object.entries(options).length > 1;
+	const expandButtonClass = !hasMultipleOptions ? 'hidden' : areOptionsVisible ? 'open' : '';
 
 	return (
 		<div className="select-container" onKeyDown={onKeyDown}>
 			<div className="select-control">
 				<Confirm
 					dropdownId={dropdownId}
-					className={Object.keys(options).length > 1 ? 'select-left' : ''}
+					className={hasMultipleOptions ? 'select-left' : ''}
 					options={options}
 					selected={selectedMethod}
 					submitAction={submitAction}
 					disabled={!!disabled}
 				/>
-					<div className={`split${disabled ? ' disabled' : ''}`}><div className={`separator${disabled ? ' disabled' : ''}`}></div></div>
+				{hasMultipleOptions ? <div className={`split${disabled ? ' disabled' : ''}`}><div className={`separator${disabled ? ' disabled' : ''}`}></div></div> : null}
 				<button id={EXPAND_OPTIONS_BUTTON} className={'select-right ' + expandButtonClass} aria-label='Expand button options' onClick={onClick}>
 					{chevronDownIcon}
 				</button>